1. Technical Field
The present invention relates to an electro-optical device and an electronic apparatus, and particularly, to the structure of an electro-optical device having a color filter including a plurality of coloration layers, which makes possible a reflection display and transmission display of colors realized by the color filter.
2. Related Art
Generally, a color filter has been formed in a variety of electro-optical devices in addition to a liquid crystal display to make possible a color display. The color filter, for example, is configured by disposing any one of coloration layers of a plurality of colors for each pixel, for example, red, green and blue, and arranging the coloration layer of the plurality of colors in a predetermined pattern. The coloration layer, for example, is formed by a photolithographic method using a photosensitive resin including a coloring material (such as pigment or dye).
Meanwhile, there has been known a display device in which the transmission display visible by the light of the backlight is realized by disposing a back light in the rear of the electro-optical device under a relatively dark environment such as indoor or in-car, and the reflection display visible by the outside light is realized by turning off the backlight under a bright environment such as outdoor. In this type of device, a light transmission region for transmitting the light and a light reflection region for reflecting the light are, respectively, provided within each pixel, whereby the transmission display is realized by using the light transmission region and the reflection display is realized by using the light reflection region.
In this case, there is a problem that the coloration layers need to be formed in both light transmission region and light reflection region to make possible the color display in both transmission display and reflection display, but since the light of the backlight passes through the coloration layer in the light transmission region only at one time, while the outside light passes through the coloration layer back and forth at two times, it is possible to achieve the bright display, but it is difficult to raise the color saturation in the transmission display, while it is easy to raise the color saturation, but it is difficult to achieve the bright display. Consequently, in general, it is necessary that the coloration layer of the light transmission region is higher than that of the light reflection region in color saturation.
Since it is necessary to change the amount of the coloring material involved in the coloration layer to give the layers of the light reflection region and light transmission region a different color saturation, there is shown a problem that the kind of coloration layer increases, whereby the manufacturing process gets complicated. Consequently, it has been known that the structure made by laminating two-color coloration layers of coloration layers of three colors such as cyan, magenta and yellow of complementary-color system is disposed in the light transmission region to form three colors such as red, green and blue of primary-color system, while the color filter for the liquid crystal display of the structure that the above-referenced two colors are, in monolayer, disposed in the light reflection region is used, whereby the brightness of the reflection display can be achieved as well as the color saturation of the transmission display can be secured. (For instance, hereinafter, see JP-A-2002-258029.)
However, in the electro-optical device that makes possible both above-referenced reflection display and transmission display, since establishing the light reflection region lowers a substantial aperture ratio of the reflection display and establishing the light transmission region lowers the substantial aperture ratio of the transmission display, there is a problem that it is difficult to secure the brightness of the display and realize the balance of the visibility of both displays.
Especially, it is necessary to secure the area of the light reflection region to some extent to consider the brightness preferentially from the luminance or contrast of the reflection display originally still lower than the luminance or contrast of the transmission display, while it is necessary to improve the display quality of the color filter of which area is within the limited range of the light transmission region to elevate the display quality of the transmission display from the transmission display requiring high display quality (contrast or color reproducibility). However, if the coloration layers of the light reflection region and light transmission region are formed by different materials to construct the high-quality transmission display, there is a problem that the number of manufacturing processes of the color filter augments, whereby the manufacturing cost is raised.